Book Image

OpenGL 4 Shading Language Cookbook - Third Edition

By : David Wolff
Book Image

OpenGL 4 Shading Language Cookbook - Third Edition

By: David Wolff

Overview of this book

OpenGL 4 Shading Language Cookbook, Third Edition provides easy-to-follow recipes that first walk you through the theory and background behind each technique, and then proceed to showcase and explain the GLSL and OpenGL code needed to implement them. The book begins by familiarizing you with beginner-level topics such as compiling and linking shader programs, saving and loading shader binaries (including SPIR-V), and using an OpenGL function loader library. We then proceed to cover basic lighting and shading effects. After that, you'll learn to use textures, produce shadows, and use geometry and tessellation shaders. Topics such as particle systems, screen-space ambient occlusion, deferred rendering, depth-based tessellation, and physically based rendering will help you tackle advanced topics. OpenGL 4 Shading Language Cookbook, Third Edition also covers advanced topics such as shadow techniques (including the two of the most common techniques: shadow maps and shadow volumes). You will learn how to use noise in shaders and how to use compute shaders. The book provides examples of modern shading techniques that can be used as a starting point for programmers to expand upon to produce modern, interactive, 3D computer-graphics applications.
Table of Contents (17 chapters)
Title Page
Packt Upsell
Contributors
Preface
Index

Creating a seamless noise texture


It can be particularly useful to have a noise texture that tiles well. If we simply create a noise texture as a finite slice of noise values, then the values will not wrap smoothly across the boundaries of the texture. This can cause hard edges (seams) to appear in the rendered surface if the texture coordinates extend outside of the range of zero to one.

Fortunately, GLM provides a periodic variant of Perlin noise that can be used to create a seamless noise texture.

The following image shows an example of regular (left) and periodic (right) four-octave Perlin noise. Note that in the left image, the seams are clearly visible, while they are hidden in the right image:

In this example, we'll modify the code from the previous recipe to produce a seamless noise texture.

Getting ready

For this recipe, we'll start with the code from the previous Creating a noise texture using GLM recipe.

How to do it...

Modify the code from the previous recipe in the following way.

Within...